Manufacture of paper making material



Patented Nov. 24, 1931 UNITED STATES PATENT OFFICE KO WATANABE, F HIGASHI-KU, NAGOYA, JAPAN mamac'ruan or PAPER MAKING MATERIAL Io Drawing. Application filed November 1, 1929, Serial No. 404,213, and in Japan February 23, 1929.

This invention relates to the manufacture of paper making material and has for its object to recover pulp of old printed paper by de-inking. l

, The characteristic feature of this invention is to make an emulsion of oily substance produced by adding to h drogen and naphthalin such as decalin an tetralin, a solvent of printing ink and dry printing ink, by the action of a suitable dispersing medium such as soap solution, glue solution and starch solution, and to mix the resultant emulsion of the said oily substance with old printed paper preliminarily treated with alkali and' thereupon de-ink the same by dissolution and dispersion of ink matter into the said dispersed solvent oil. Y

The ob'ect of this invention is to attain the de-inln'ng of old printed paper easily and completely and torecover useful paper making materlal of the same grade as that of the old paper used, by a simple and economical process.

Heretofore old printed paper has not been utilized as a raw material for the recovery of high gradepaper pulp on account of the difiiculty of de-inking. But, by the improved method of such invention this old printed paper may be satisfactorily used as p a raw material for the same purpose, and also a successful utilization can be attained of old printed paper, which is of great demand.

The execution of this invention is as follows To make an emulsion of hydrogen and naphthalin, a solution of soap as the disper'sing medium made of any sort of fats or oils such as soap of sesame oil is used.

To explain this more fully about lbs. of such soap of sesame oil is dissolved in a proper quantity of water, this solution is then mixed with about 20 litres of tetralin, the resultant mixture is then violently agitated, thus producing the emulsion of tetralin.

The next treatment is the tearing or break into the kneading machine through respecing up of old printed paper. For this pur-.

"of this paper mixture old paper is greatly softened by the action of coexisting chemical caustic soda, so that the kneading action proceeds much easier than when kneaded with water only.

The kneaded paper mixture, which is black in colour, is discharged from the kneading machine, and then poured down into the paper making potcher or the mixing machine and now the emulsion of tetralin is added to this mixture then the whole of this is agitated by constant rotation for about thirty minutes. During this agitation in the potcher or the o5 mixing machine dry printing ink on old printed paper is completely peptized into minute particles, and as a result of this the pigment contained in printing ink, such as lamp black, is also completely suspended in the dispersed solvent oil. This dispersed mixture, therefore, contains minute particles of peptized ink, matter so that when one scoops up and presses this mixture between the'hands a blackish muddy liquor will be separated from the mixture and a white paper fibre will remain in the hands.

poured again into the potcher or the mixing machine with water and thereafter repeatedly washed by the drum washer or it may be poured down into a tank having a mat stretched over the bottom and provided with agitators and in this tank the muddy liquor is filtered and separated.

In actual practice of this washing process, there rarely appears minute black spots on the washed pulp mixture even if the quantity of the latter is very small. But these spots may be completely removed by wash ing and adding a small quantity of alkali, as said phenomena of black spots chiefly appear owing to a lack of the -alkalinity of the kneaded paper mixture. Moreover this removing effect is better attained when a small 7 quantity of soap is added with the alkali. The resultant product after washing is completely de-inked and the fibre consisting of old rinted paper can thus be obtained.

T e produced material thus gained is then made up into dry pulp by a wet machine or into paper by being directly poured into a beater.

I claim: Method of manufacturing paper making material'consisting in preparing an emulsion of oily substance including hydrogen and I naphthalin with a solvent of printing ink and dry printingink, by the action of soap solution as a dispersing medium and then mixing the resultant emulsion with old printed paper preliminarily treated with alkali and thereupon de-inking by the dissolution anld dispersion into the said dispersed solvent 01 In witness whereof I have hereunto set my hand.

KO WATANABE. 

